Re: [syzbot] [crypto?] KASAN: slab-out-of-bounds Read in arc4_crypt

From: Edward Adam Davis <eadavis@qq.com>
To: syzbot+8ffb0839a24e9c6bfa76@syzkaller.appspotmail.com
Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [crypto?] KASAN: slab-out-of-bounds Read in arc4_crypt
Date: Wed, 20 Dec 2023 14:34:55 +0800	[thread overview]
Message-ID: <tencent_2D9956CFC10D9425B98DCE12085DBEDDB607@qq.com> (raw)
In-Reply-To: <000000000000d52e14060cc9c551@google.com>

please test slab-out-of-bounds Read in arc4_crypt

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 17cb8a20bde6

diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 02cea2149504..1c50f6e3f334 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -120,6 +120,10 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
 	if (IS_ERR(areq))
 		return PTR_ERR(areq);
 
+	printk("req: %p, areqlen: %u, %s\n", 
+		&areq->cra_u.skcipher_req, areq->areqlen, __func__);
+	if (areq->areqlen < 1032)
+		areq->cra_u.skcipher_req.__ctx = kzalloc(1032, GFP_KERNEL);
 	/* convert iovecs of output buffers into RX SGL */
 	err = af_alg_get_rsgl(sk, msg, flags, areq, ctx->used, &len);
 	if (err)
diff --git a/crypto/arc4.c b/crypto/arc4.c
index 1a4825c97c5a..79621f4f4c68 100644
--- a/crypto/arc4.c
+++ b/crypto/arc4.c
@@ -29,6 +29,7 @@ static int crypto_arc4_crypt(struct crypto_lskcipher *tfm, const u8 *src,
 {
 	struct arc4_ctx *ctx = crypto_lskcipher_ctx(tfm);
 
+	printk("%p, flags: %u, ctx: %p, %s\n", siv, flags, ctx, __func__);
 	if (!(flags & CRYPTO_LSKCIPHER_FLAG_CONT))
 		memcpy(siv, ctx, sizeof(*ctx));
 
diff --git a/crypto/lskcipher.c b/crypto/lskcipher.c
index a06008e112f3..4dda11ce6536 100644
--- a/crypto/lskcipher.c
+++ b/crypto/lskcipher.c
@@ -215,6 +215,10 @@ static int crypto_lskcipher_crypt_sg(struct skcipher_request *req,
 
 	flags = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP;
 
+	printk("r: %p, ivs: %p, v: %d, s: %u, ri: %p, wi: %p, f: %u, wnb: %u, am: %u, %s\n", 
+		req, ivs, IS_ERR_OR_NULL(ivs), ivsize, req->iv, walk.iv, 
+		req->base.flags, walk.nbytes, crypto_skcipher_alignmask(skcipher), __func__);
+
 	if (req->base.flags & CRYPTO_SKCIPHER_REQ_CONT)
 		flags |= CRYPTO_LSKCIPHER_FLAG_CONT;
 	else
@@ -224,6 +228,9 @@ static int crypto_lskcipher_crypt_sg(struct skcipher_request *req,
 		flags |= CRYPTO_LSKCIPHER_FLAG_FINAL;
 
 	err = skcipher_walk_virt(&walk, req, false);
+	printk("ivs: %p, v: %d, s: %u, ri: %p, wi: %p, f: %u, wnb: %u, %s\n", 
+		ivs, IS_ERR_OR_NULL(ivs), ivsize, req->iv, walk.iv, 
+		req->base.flags, walk.nbytes, __func__);
 
 	while (walk.nbytes) {
 		err = crypt(tfm, walk.src.virt.addr, walk.dst.virt.addr,
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index bc70e159d27d..08409990b58a 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -716,6 +716,8 @@ static int crypto_lskcipher_import(struct skcipher_request *req, const void *in)
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	u8 *ivs = skcipher_request_ctx(req);
 
+	printk("%p, csa: %u, csi: %u, tfm: %p, in: %p, %s\n", 
+		ivs, crypto_skcipher_alignmask(tfm), crypto_skcipher_ivsize(tfm), tfm, in, __func__);
 	ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(tfm) + 1);
 
 	memcpy(ivs + crypto_skcipher_ivsize(tfm), in,

